English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The performance optimization for a combined ascent-entry mission subject toconstraints on heating rate and heating load is studied. The ascent vehicle ismodeled as a three-stage rocket that places the vehicle onto a suborbitalexo-atmopheric trajectory after which the vehicle undergoes an unpowered entryand descent to a vertically downward terminal condition. The entry vehicle ismodeled as a high lift-to-drag ratio vehicle that is capable of withstandinghigh levels of thermal and structural loads. A performance index is designed toimprove control margin while attenuating phugoid oscillations duringatmospheric entry. Furthermore, a mission corresponding to a prototype launchand target point is used in this study. The trajectory optimization problem isformulated as a multiple-phase optimal control problem, and the optimal controlproblem is solved using an adaptive Gaussian quadrature collocation method. Akey aspect of the optimized trajectories is that, for particular ranges ofmaximum allowable heating rate and heating load during entry, relatively smalladjustments made during ascent can potentially decrease the control effortrequired during atmospheric entry. Outside of these ranges for maximumallowable heating rate and heating load, however, it is found that the requiredcontrol effort increases and eventually saturates the commanded angle of attackupon initial descent. The key features of the optimized trajectories andcontrols are identified, and the approach developed in this paper provides asystematic method for end-to-end ascent-entry trajectory optimization.

End-to-End Ascent-Entry Mission Performance Optimization Using Gaussian Quadrature Collocation